QLabel does not repaint QPixmap

[__Emanuel]

Yes, but if it's race condition and timing issue, than why it's possible to get smooth playback on both videos if manually change main window resize. As long as i change it, it repaints both label frames and nothing stucks. Once i stop changing size, the same label that was stopped previously, stop again. Though that timing issue should keep blocked forever even if i resize it.

I am definit that the race condition is not in frame receiving. I monitor the frame receiving on the place where setPixmap used. And it shows that frames are coming consequently to both. But highly possible on QT repaint. Maybe it stuck on update specific label. If i set pixmap on one label, is it true, that it can affect the state of other label context ?